Electronic Device with Isolated Cavity Antennas

1. A portable computer, comprising: a housing having an upper metal housing that contains a display and having a lower metal housing that contains a keyboard; hinges that connect the upper metal housing to the lower metal housing so that the upper metal housing rotates relative to the lower metal housing about a rotational axis between a closed position and an open position; first and second cavity antennas mounted in the lower metal housing between the hinges, wherein the first and second cavity antennas have conductive grounded portions that form first and second respective antenna cavities for the first and second cavity antennas; and first and second conductive gaskets that short the first and second antenna cavities to the lower metal housing.

2. The portable computer defined in claim 1 further comprising plastic structures and metal traces on the plastic structures that have portions that form the conductive grounded portions.

3. The portable computer defined in claim 2 further comprising first and second speakers in the plastic structures.

4. The portable computer defined in claim 3 wherein the upper metal housing has openings that form first and second ports for the first and second speakers, respectively.

5. The portable computer defined in claim 4 wherein the first conductive gasket has a ring shape that surrounds the first port and wherein the second conductive gasket has a ring shape that surrounds the second port.

6. The portable computer defined in claim 5 wherein the first and second cavity antennas are located between opposing upper and lower portions of the lower metal housing and wherein the first and second conductive gaskets short the conductive grounded portions to an inner surface of the upper portion of the lower metal housing.

7. The portable computer defined in claim 1 further comprising: control circuitry in the lower metal housing; and a signal path that is coupled between the control circuitry and the display.

8. The portable computer defined in claim 7 wherein the signal path comprises a flexible printed circuit having signal paths surrounded by first and second ground traces.

9. The portable computer defined in claim 8 wherein the first and second ground traces are shorted to the upper metal housing and the lower metal housing.

10. The portable computer defined in claim 9 wherein the first and second cavity antennas are dual band antennas.

11. The portable computer defined in claim 10 wherein the first and second cavity antennas are each configured to operate in communications bands at 2.4 GHz and 5 GHz.

12. The portable computer defined in claim 11 further comprising conductive structures that short the conductive grounded portions to an upper surface of the lower portion of the lower metal housing.

13. The portable computer defined in claim 12 wherein the upper metal housing has a rear metal portion that is separated from the lower metal housing by a slot when the upper metal housing is in the closed position and wherein the first and second cavity antennas receive antenna signals through the slot.

14. A portable computer, comprising: a housing having an upper metal housing that contains a display and having a lower metal housing that contains a keyboard; a flexible printed circuit that extends between the upper metal housing and the lower metal housing, wherein the flexible printed circuit has metal traces that are shorted to the upper metal housing and the lower metal housing; hinges that connect the upper metal housing to the lower metal housing so that the upper metal housing rotates relative to the lower metal housing about a rotational axis; and first and second cavity antennas mounted in the lower metal housing between the hinges, wherein the first and second cavity antennas have metal traces forming conductive grounded portions that are shorted to the lower metal housing and that form first and second respective antenna cavities for the first and second cavity antennas.

15. The portable computer defined in claim 14 wherein the first and second cavity antennas have inverted-F antenna resonating elements and wherein the metal traces are supported by plastic support structures, the portable computer further comprising first and second speakers in the plastic support structures that are mounted in alignment with first and second sets of openings in the lower metal housing.

16. The portable computer defined in claim 15 further comprising first and second ring-shaped conductive gaskets that short the conductive grounded portions to the lower metal housing in alignment with the first and second sets of openings in the lower metal housing.

17. The portable computer defined in claim 16 wherein the ring-shaped conductive gaskets comprise foam.

18. The portable computer defined in claim 17 wherein the first and second cavity antennas transmit and receive antenna signals in communications bands at 2.4 GHz and 5 GHz.

19. A portable computer, comprising: a housing having an upper metal housing that contains a display and having a lower metal housing that contains a keyboard and control circuitry; a flexible printed circuit that extends between the upper metal housing and the lower metal housing, wherein the flexible printed circuit has first and second metal ground traces that are shorted to the upper metal housing and the lower metal housing and has signal traces between the first and second metal ground traces that convey signals between the control circuitry and the display; hinges that connect the upper metal housing to the lower metal housing so that the upper metal housing rotates relative to the lower metal housing about a rotational axis; and first and second cavity antennas mounted in the lower metal housing between the hinges, wherein the flexible printed circuit is located between the first and second cavity antennas.

20. The portable computer defined in claim 19 wherein the first and second cavity antennas are formed from metal traces on a plastic speaker enclosure and wherein the metal traces on the plastic speaker enclosure have portions that are shorted to the lower metal housing by conductive structures.